Senior Information Systems Security Officer

Senior Information System Security Officer (ISSO)We are looking for a Senior Information System Security Officer (ISSO) to support a critical U.S. government agency in the National Capital Region. This role reports to the Security Program Management Office (SPMO) Manager and works directly with team members and Federal ISSOs to support authorization, compliance, continuous monitoring, and risk management activities across assigned systems.This is an excellent opportunity for an experienced cybersecurity professional with a strong technical background to support the secure authorization and ongoing compliance of systems across on-premises and cloud environments. This is not a hands-on engineering position. Instead, the Senior ISSO leverages prior experience as a Systems Administrator, Cloud Engineer, Infrastructure Engineer, Network Engineer, Security Engineer, or similar technical role to independently validate security implementations, assess technical risk, and ensure authorization decisions are supported by accurate technical evidence. The successful candidate must be comfortable engaging engineers, architects, and system owners to validate security controls, identify inconsistencies, and challenge unsupported technical assumptions. Hybrid: 3 Days On-site in Washington, DC / 2 Days Remote Must be able to obtain a government security clearance requiring U.S. Citizenship or Permanent Resident Status Responsibilities:Support the security authorization lifecycle and ongoing continuous monitoring activities for assigned systems.Develop, review, and maintain security documentation and authorization artifacts, including SSPs, SARs, POA&Ms, SIAs, and related documentation, in accordance with NIST SP 800-53, RMF, FISMA, and agency policies.Coordinate and prepare systems for Security Control Assessments (SCAs), ensuring documentation and evidence are complete, accurate, and technically defensible.Conduct Security Impact Analyses (SIAs) for changes to hardware, software, cloud infrastructure, connectivity, or system architecture.Review system architecture, technical documentation, and supporting evidence to validate security controls, independently assess technical implementations, identify inconsistencies, and collaborate with engineers, architects, administrators, and system owners to resolve discrepancies.Support change management, continuous monitoring, POA&M management, risk acceptance, audit responses, and remediation activities to maintain ongoing authorization and compliance.Coordinate with system owners, engineers, architects, and governance stakeholders to support standards reviews, exception requests, policy implementation, compliance reporting, and risk management activities.Develop dashboards, executive risk briefings, status reports, and other stakeholder communications while supporting the Lead ISSO in operational execution and coordination activities.Required Qualifications:Bachelor's degree and 6+ years of relevant experience, or a master's degree and 5+ years of experience, in cybersecurity, RMF, ISSO, systems security engineering, systems administration, cloud engineering, network engineering, or a related field.Ability to obtain and maintain a public trust requiring U.S. Citizenship or Green Card.Prior hands-on experience in a technical role such as Systems Administrator, Cloud Engineer, Infrastructure Engineer, Network Engineer, or Security Engineer, with the ability to evaluate technical implementations, validate controls, assess evidence, and challenge unsupported assumptions.Experience supporting federal authorization activities, including SSPs, POA&Ms, SIAs, continuous monitoring, and Security Control Assessments.Working knowledge of NIST RMF, NIST SP 800-53, FISMA, and federal cybersecurity requirements.Familiarity with enterprise and cloud technologies such as AWS, Azure, Microsoft 365, Entra ID, Active Directory, VMware, Cisco, Oracle, or similar platforms.Working knowledge of identity and access management, encryption, system hardening, network and cloud security, secure baselines, logging, and monitoring.Experience with GRC or security authorization tools such as Archer, eMASS, JCAM/CSAM, Xacta, or similar platforms.Strong analytical, technical writing, organizational, and communication skills, including demonstrated professional proficiency in written and spoken English. Ability to independently produce polished, technically accurate documentation; communicate clearly and effectively with technical and non-technical stakeholders; work independently; and manage competing priorities in a fast-paced environment.Proficiency with Microsoft Word, Excel, PowerPoint, and SharePoint.Preferred Qualifications:Security+, CGRC (formerly CAP), CISSP, CISM, CCSP, or similar cybersecurity certification.Experience supporting federal systems, ATO processes, FedRAMP, federal privacy requirements, or other government compliance programs.Knowledge of modern cybersecurity practices including OWASP Top 10, Zero Trust, application security concepts, and MITRE ATT&CK.Experience participating in incident response, security architecture reviews, technical design reviews, or security remediation efforts.Experience operating in fast-paced, high-visibility environments with competing priorities.We offer:Competitive salary based on experienceProfit sharing distributed twice a year15 days of paid time off and 10 paid holidays per year401(k) with employer matchingHealth and dental benefitsOpportunity to work with other talented technical professionalsSharePointXperts is an Equal Opportunity/Affirmative Action employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, national origin, disability, or protected Veteran status.